Microstructural evolution in Fe and Fe–Cr model alloys after He+ ion irradiations

Thermal desorption spectra (TDS) analysis and transmission electron microscopy (TEM) observation were performed to investigate microstructural evolution in Fe and Fe–X at.% Cr (X=5.0, 15) model alloys during thermal annealing after irradiation with 8 keV He+ ions at room temperature. TDS analysis showed that there is not so much difference in He desorption during post-irradiation annealing between Fe and Fe–Cr alloys, but the amount of He desorption depended on the Cr concentration of the samples. As for TEM observation, a number of interstitial dislocation loops was observed in all the samples even before post-irradiation annealing, while He bubbles were observed in all the samples only after annealing at temperatures greater than 773 K. Microstructural evolution observed by TEM also depended on Cr concentration. The effect of solute Cr addition on the mobility of interstitial loop and He bubbles is discussed.